SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4364aa04d6e065e81f16fa2bd131870b01baf63f7bc1e56901ce3a0532a526f9' 
  AND token = 'zIzjE2QD464hqGv9UJv2qA+9+rhDPnqqknXkoJHOlcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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