SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd29059274d7ce3e52b85236a18a27d34373e5ec00ad475c5e7288b1a091892a2' 
  AND token = '7dhZEbL3hrKvKe8KgaeNn6/pNIutiIO+PxXrvGgSUqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}