SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a746d81758f615606ffdf6065842e230b3e521879e15d7e73f9258ebddb7a5' 
  AND token = 'Q/n+pB8D4rAPMHnFTf18xq9il2R8Q6krghA2nYQbHUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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