SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0a52e259cc309c6be18f0e745c79aa054322fe17cb42207668302fd5744c10e' 
  AND token = '8VtcP6HBAEgMuUG+yaeRMdoGOidQN9Gjv0sqjm4UtZE=' 
  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"
    }
  }
}