SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30637e50e91fa69fbaf958c2f3b1746c8c2194279346a3d4f26bda2d1551748b' 
  AND token = 'x2FGW2PxPtqruIq9QsTXxIABbzH9CHNTYFw9w1nZh28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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