SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbb78b308983c90fa3a363c3d7d6bf26affce9d0b6d460b1fabb17485ed04f68' 
  AND token = 'In6IYAH422LJbrRqpLnuVMMc4JcGOtv4Pk1KAOPbs9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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