SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1a89edbede36120f1529c55a1543359ee8cf1dcb408c9f9609e50ba44b4f77' 
  AND token = 'ngAgQAE4sKxYwzbcbkVZy/nnfuWpVHHTHI0s+b08kIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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