SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6993a9b038258aaa8d8d6bf5d51e40b411925cbd5d3b00840a369e83b9e3cd4e' 
  AND token = 'kNZCib5NzwlCCau3lKpgEK5i4vO4QygeJyqVVlPtsc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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