SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a675d9fb508cb7ad98cb1aa4c55c7f4790f444a689fdb73dd56520dfdfb7f78c' 
  AND token = 'MbEET/VT2wAS+SRnT35x9PTCpGPCYz2JBrm0Igg9ZX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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