SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48f0c28154d6b01c87c66a9be0a1d4c0786e19570b5ade8b2134429b99ae048f' 
  AND token = 'VsimaTnS+YGSum6pmxo+MIKfPdhRYYs/kahZKK/XS3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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