SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8f27b3dd167b1b831dd80efd9041f5d755dabce14d246d662e55a5f55905c4e' 
  AND token = 'b6abzA5QNfFq6qeE9U5CKD/YXFwNffdSOGhfr8g6boM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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