SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '279aa592ebd644821c9649f6add7d6346826c1b324b5593293a276f8d7cf351a' 
  AND token = 'ZQJT3cfBl6W8r4bzSBXP+7kk5NQhYieH/wX+PawnWNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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