SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12ce12e46983ba13cdaa9826512a8766d7ab4ae63a545aed21a97da62f1ca96d' 
  AND token = 'f++fRq/00XYbUs71oj/XS7aClDpYpq2mkJwjCG/ouCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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