SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6267f95982848b7baa01069db7e70dbc09cac72ca4d944bf2af2f322c9714be' 
  AND token = 'TTVOgB0Ty+68V3pvo0l6kGvjCx+Df9cD3rG+HAC0F3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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