SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e6efdae647d8f66f7243725611118d5cbda625fd93ec190e141859a6594da044' 
  AND token = 'wpDxhkRh3E4B0zhniQCvTZYq3VeoCa+EF/Jl+mVTUvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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