SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7fdaf5a8da334c6b1c85b5bb1d660522fee7a1c4fd2d48fb91eb124cd8edb30' 
  AND token = 'Ei1qqBgunCev1RWr/BnP4lomjRF90F+/XAmWHt8lz4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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