SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc63a93002e66c1f3bd9ac652b84ed8dcab460b1189ff081e26dfcf587204bff' 
  AND token = 'b6h9qkDFcXQepImi/juEqfGmin4RETjGzRHb4uIVuPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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