SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31af46a58daacb59b3f4d7536de3937a5180fc8243c7d46004dc7c5541796317' 
  AND token = 'e/xdgQPLUKYvXUp25HipunwUoK7oEyhetHzTs0x2s8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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