SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8d6db33dec81501427379541a1c2b702e411148716bcd3f2909fe42ed18aad2' 
  AND token = 'qweEkfajhLoEmskuG21cyUZYdGLuJ/nBfF1Pdjuq0/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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