SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b8d1f510f6d7714a67d08049dfdd7cf9fb5ad92bedf707370869c7d4afa3550' 
  AND token = 'ofLsR25PlOxAnupjarKju8KwOpo+d/m1yyZiv1WdfRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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