SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81ff27f0860b568543ee3178ace2abcaf2c585cb648322558ff3b54e7bcdf9c8' 
  AND token = 'NH3DeBdqhVuUIXwtgXAFJ74u1aZjEfnA7tYn00i1IhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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