SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52aec497e1a18487034ccd44322f7e87cd65ea80f26ac0b4d8b3a33cea10bea1' 
  AND token = 'TAnMxsPnF8bcBYVpIuCnmgkCCY/gVaMIVQRloLDsTUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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