SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a391efb9d039d6a95d787905b52e1526577dcca3428a675dbc0b05a9258f50a' 
  AND token = 'tHR2SGCc2COzmwamXnb1FQujKtuJn7MbJ7j+Irsno2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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