SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ee73bc93b0443e2063372377fec8a2cdad39f2da2cb7325684bad81d86d69df' 
  AND token = 'TZqeGqZLABTgPCCohh0T+1Rgz+U3fj37fxSl4umIxKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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