SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '106fe42251912a1cf2cfb849ebad4d57de22e2bb6d72e780432f25f15a0bfc7b' 
  AND token = 'LDjgUVRHAE31WempMqflpLoA2TppebTxSPdi1spUG7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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