SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4cedb81f4082be714fb917c6af32e7f466b93cc85d5f7c7f8edbc71a5fbbc68' 
  AND token = '8Dyf0lE3Npza2x3F3trCq1sA8hw9htYPMUIGEUdSi48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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