SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c9a376a8d0291cd64337b08e1de94964b44f5ca0db9097931a8c32013d6fd66' 
  AND token = 'kWYL7AUFN0bfZ0/7QAkwNN4QElaQn1/AaqhozhcFNO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}