SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9790d70895d0485cc9d8ae1cf9080657f4ac99529369dd222d2863398be63f3' 
  AND token = 'dpxyxilkaeEKGsYOgsC/8AAS/kclto6SpBnetrZsfXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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