SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f97ec1ce0ff55452ac88554b477cbee771d2a3a5e0f557c94f17688ddf297fc7' 
  AND token = 'AHUYW6GVpa4KsQgDcYHqiwQyuMeDmBmkL3dwEs80rhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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