SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f125509b6c5e78ae0e50efb935514dd3693003b052578314d1674b743d3d594b' 
  AND token = 'RlUKhp5JEipLz1ht9BEhpW1DA5iU+a0NP6xQyCxMSww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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