SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b7457084e9d84c28bf56ab8a3a891966b7541bb5877d7f94e17edad29c71f33' 
  AND token = 's/v6vLks/zLtTgb2zZEq+k6pJIB4WUb+3gR/fejQbGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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