SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebfc563da828d94d6cb523ccf392d6c0f80c634b3feb686c4dc75e49f31919f0' 
  AND token = 'FGgiHC2uyhm2XpYrVLe7CpGymadvrAIswcgt/3jniYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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