SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e4e0451258081bedab2cddde6da4150074802ad6785306951e8f7dea7af437fa' 
  AND token = 'WMOouNtYJuzfOF1SRJgys1XYpxfPVT8nM19506zLxac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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