SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '35f48431a477db509033fe178495a47b96a0fafaf91afbce07267ad5ba491b0d' 
  AND token = 'yc3T+z/ZBknuPexQwOFTjjyXrNcp0tq7zWILbVRL/Bg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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