SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '24a0b885495ba737a18c978a5542c96a50ad5e75afa906fb21abc2c7c52dce42' 
  AND token = 'KyxyJ2DoZQHMhqRvOsRQ0+2GXmdzwVchZknrydtWrIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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