SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '99c4996a513b4abea1f0684e90f30b4acd35679990ce5fda527af98041d94bc9' 
  AND token = 'siEqwQk6wwBDeNnM+3ls3yFINtxgC30RiISpNemQjNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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