SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c45ad391d540d3b1864dd4564a1a5ff2fa0e96f01bae4bff2be946c6e88994a' 
  AND token = 'VugpLgG7VCBxETQ6zJ9qFE//3Z7wxkbBV00LaBLEWKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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