SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f55022273a1a04ff008dea2f844fe318cc2aae24216b777ebc7f047d8aaf6216' 
  AND token = 'B9a+/l0ocFHmyUB9kA5AEISsTfOPtxdqTdUcDfTy87o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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