SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1a9920b7c603215f12c06c8f38ff4a4025209823fbe214cbfd64e84f3978736' 
  AND token = 'nh/T6EC71bx/kz98kEivI9JPGUxlqVZTS+TBfX4sDSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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