SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '261794d4ac7de96311815cb731a2cba70c04411af333107c2e66ae4f0c46ca0b' 
  AND token = 'DGEzpNX7hwqbvOPsY0fHJbqYXP1XKA6gsGWXPtE6q6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}