SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a9556417c2196f06ca6b40338f2641532737d3c4052860602f016340a7034ae' 
  AND token = 'WV7Kp+t8z3UzpQlE4AflRmTpWSRfo1ia+gIghLjWjz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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