SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b53abc74bb3808570c507f4e110425b82428c86b4933097c06e3ef77285ec398' 
  AND token = 'vV4uLQmSTGXDyZqBRNmwogtO/amuKsir0PMqmviIf8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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