SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a908d3650ff80ccd0bc94fe7781e368fa1daa2fd5539229508bd18755904680' 
  AND token = 'g2DV42rlODdt8DOmOF2QzQKRThdphFoLFuCH/atT2fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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