SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c7955ec50154011e0974ba862bd20ca6d99283e50e96477c4bb39b84611807' 
  AND token = 'whfcXNcnn6myZUWHFxuC58pwDQ2eS00QJ3KLUVbp4OU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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