SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '287e11a028fa9b3114397f16181d06d32d3b9d2030c014545c4820234cf2ef11' 
  AND token = 'LUNOFfsm6M7cYHwpcoPw+ySZN/DIodP+fb4DUAbLefA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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