SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90a05a022a8d2ccdd53242d29ca28b4968b73675fdeae36387189e76519729a1' 
  AND token = 'JYJowoNGq/y3AdEQYua5APKyxdp3DykdJadj94D/Ujw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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