SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b1d3ff1e4b9116dbee0be03100c2edc147ded7ac9067f0e1605e380c500cbef3' 
  AND token = 'DV49OvU67udO2A72J+FQbuows/E88QMjPipuQnRNLAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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