SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '876db18534014c8932e86b6c74d08fd729d34dc9dd39f3e3c516175a830a56f9' 
  AND token = 'zOL+7+hG7nkiTRTfEIiKnucPAUsQKigC3g+8oW2i3vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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