SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e41a248ef8646bf68a0908945294f1cf1c24afc826d9f6109fc6394214f96021' 
  AND token = 'ng5icRW1+YJsFJsk0rQ5xzm2sjoR4IjHfgFdpQEw9Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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