SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9d7f4abd94e865da58d3d386505d0da59853910e59e77aaf20125bfb8cf0b75' 
  AND token = 'R2rsTSnHkXPXRhWHDz0b5bRbFofe+nxVoNX/VCkzBnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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