SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e1017c6da2cadc918ca51e2160084acfb4abac4895ed32b73a0e26c333fcf8' 
  AND token = 'FhN85mw2UadXPMjTHO6B1F8u9a31v5uSpt+lNldlcs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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