SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '210a1b78725f69a1371c8f0215fd6e698e6d32382af7bca75d50b2fccfb2073f' 
  AND token = 'rNFxgyVF8b8gPk//ocOkAQYISdEroYdO7q1M8RSudHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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