SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c2be4190b67091055bb71e50934f75cd13cf28f4b3b92672724572d0a78e238' 
  AND token = 'STo9Kpy5BWnTk7ZVIytG5qA3Fjmq6YY2sxgvho2nx18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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