SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88238c56319c1ca215e875b7f37d935defe2e3ad3abcf71bf1ecbcc55bdd4671' 
  AND token = '87nn7XSI1QOfxT0lIIDgvOrX1gZv22gvc8SE/KOcyxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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