SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1c9f8f0bc678b8927056d3ceaf9526e83d64f01a286d049397dab9c4f2a8e16' 
  AND token = 'ZjmjOWv6GPUzyM4FCFKNTqT6U6rGuJBcHsxAOSHo36o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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