SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77b3dc1b09eec196c1c32b5fc069aca0e835f0e1f727837aa4c061a62a7a5e0a' 
  AND token = 'j10sKg/Tof0D7EEURGB6b76nPbC959LxQnOBDNgD2sU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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