SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4d8f81785f06cce27924241288406811e13b1dd1ad3a6c776bf202a976894cb' 
  AND token = 'oAc1evDBllNZwvPB3COhXJ3OPtjII0YoATL/HTihTZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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