SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17c0b7fba7777ff75d7fdfd13bf232cb4e476abec27054e7d3f83fce81c2860d' 
  AND token = 'b52BM4t1mQ6YaAdwTOO7pSWx6Oma8ukB9Lh1/HMsaKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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