SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3ff5513250c2d42a1aac4285fa7afb94b4af587050725a4a19c197cbb12e9a5' 
  AND token = 'i2Obcc+sNvu1QIQ32gb7bnh1WlQFiguU+X3KxAIWDg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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