SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194a9f2d657cd2e6e61d56b92353ac215e24509d31c6369c1e50a308715a2d6c' 
  AND token = '9eNBJhGXl12zwctOFkqgZVaFZANzggivNftKGnHhYq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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