SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '396175c55c1ffb86c17c04d67b12d7e42cb33868eecebc5ca945008e6f9d6421' 
  AND token = 'f8uuP4CbTHEvnHpSlAezKKFYqmDWeLNegXZ8KXqk/Sw=' 
  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"
    }
  }
}