SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8e39c73589e0e83733dc0e9b92beb8707f9663eb77d824896257a4ee3f794dc' 
  AND token = 'jzZXNSuIEMBCRLHJmVV6UggCea0wCw/fbuYv1OnRcfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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