SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18143861375cbec0f608c96e252b646cb861a933274ab47000ca2d37de6e40e7' 
  AND token = 'RkxgzWqDQ3HVLJAunlPqUyw716yogY9OschbUmEOXIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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