SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ab807b23b927ad066bc56a99cedcb94dfb850d22d0a1a22acdcfbf281cf43824' 
  AND token = '/LPXvuBHWoBeCe4YGK3FVMB88qf93jaQco/nZz0V6JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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