SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a53a168ba97e618fc7ac370b100e9cacd43af28c22102356be4c1af5806a650' 
  AND token = 'YFKJVKCuXVmNgIj0H1zphHNxaJZtowjGbfdxcV6V45U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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