SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4914a2f37124495051dae8e1302b141a7771ef520ed96850090e5cdbb184d4d7' 
  AND token = 'EZcDtXPIdwboL5qU0djjFVrhf2rU5ukWRFQR5UaH9bs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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