SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c44d93b33961c6a5957734182d7203944dbcb88e3f21c132820d7c58c76d5bea' 
  AND token = 'FHfZ2S38hbO+z3+FWeGAhVupHMDZ/iCF5WM1bdBs8Zg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}