SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '908e601e31c5af89e949083294227f844483bd0c771f708f2dac68cea25eec6e' 
  AND token = 'JjEq3/aHsN9D3jUjqqwwd2WmB6z3BIVwmDUl07BUKyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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