SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b20d0c7baa5dff52467c9dd2d94386c5a07e288fc7abefca4bf2c02de08d6baf' 
  AND token = 'UcaY9sjfDLkjDOJlfnRUOa4BfTpwjFQ4cekOgyMcNkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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